package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Autowired
    private IUserService userService;

    //关注和取消关注
    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        //获取登录用户id
        Long userId = UserHolder.getUser().getId();
        String key = "follows:" + userId;
        if (isFollow) {
            //更新数据
            Follow follow = new Follow();
            follow.setUserId(userId);
            follow.setFollowUserId(followUserId);
            boolean isSuccess=save(follow);
            if (isSuccess) {
                //把关注用户id放入redis的set集合
                stringRedisTemplate.opsForSet().add(key, followUserId.toString());
                //为啥要放到set集合中 因为set集合有一个特性 可以判断两个集合的交集 所以可以判断两个用户是否共同关注了某个人
            }
        }
        else {
            //取关
            LambdaQueryWrapper<Follow> queryWrapper = new LambdaQueryWrapper<>();
            queryWrapper.eq(Follow::getUserId,userId);
            queryWrapper.eq(Follow::getFollowUserId,followUserId);
            boolean isSuccess =remove(queryWrapper);
            if (isSuccess) {
                //从redis的set集合中移除
                stringRedisTemplate.opsForSet().remove(key, followUserId.toString());
            }
        }
        return Result.ok();
    }

    //判断是否关注
    @Override
    public Result isFollow(Long followUserId) {
        //获取登录用户id
        Long userId = UserHolder.getUser().getId();
        LambdaQueryWrapper<Follow> queryWrapper = new LambdaQueryWrapper<Follow>();
        queryWrapper.eq(Follow::getUserId,userId);
        queryWrapper.eq(Follow::getFollowUserId,followUserId);
        long count = count(queryWrapper);
        return Result.ok(count>0);
    }

    //查询共同关注

    @Override
    public Result followCommons(Long id) {
        Long UserId = UserHolder.getUser().getId();
        String key1 = "follows:" + UserId;
        String key2 = "follows:" + id;
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(key1, key2); //求两个集合的交集
        if (intersect==null||intersect.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = intersect.stream().map(Long::valueOf).collect(Collectors.toList());
        List<UserDTO> userDTOS = userService.listByIds(ids).stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class)).collect(Collectors.toList());
        return Result.ok(userDTOS);
    }
}
